1. Field of the Invention
This invention relates to a hair combing apparatus and, more particularly, to a hair combing apparatus for monitoring combing force.
2. Description of the Prior Art
A problem frequently encountered especially by people with long hair is a condition known as "split ends". "Split ends" are produced when the cuticle is stripped off a hair fiber by excessive combing force. "Combing force" refers to a force experienced by a hair tress when a comb is pulled through the tress. "Grooming force" is a generic term referring to that same force applied by any type of grooming means, including combs and brushes. Combing force will be used throughout this specification since it is the more commonly accepted term, however, it will be appreciated that the same considerations apply to measuring both combing force and other types of grooming force. "Hair tress" is used to refer to a lock or curl of hair either separate from or growing out of a person's head. When measuring the force used to comb a hair tress, a comb experiences resistance throughout the length of that tress. Two terms used frequently to describe that resistance are "total combing force" and "incremental combing force". Total or cumulative combing force is a summation of the forces encountered over an entire stroke, whereas the incremental combing force is the force encountered at any single point along a stroke. The maximum incremental combing force encountered during the course of a stroke is known as the "peak combing force".
Apparatus for measuring combing force are well known in the prior art and generally consist of three major types. The first, an example of which is described in U.S. Pat. No. 3,459,197, comprises a flexible comb with mechanical means for measuring the peak deflection of the comb and relating it to the peak combing force applied during one complete stroke of the comb. After each stroke of the comb, the user must record the reading and reset the indicator to zero.
The second type of apparatus includes large complicated testing instruments requiring a hair sample to be attached to a transducer cell within the apparatus. Such devices are not useful for measuring the combing force experienced by hair while it is still attached to the head.
The third type of apparatus, an example of which is described in U.S. Pat. No. 3,928,558, comprises an aluminum comb fitted with a strain gage. The voltage output resulting from the movement of a tress of hair through the comb is summed by an integrator, a device which produces an output proportional to the integral of one variable (combing force) with respect to another (time). The output from such a device, at any point in time, reveals only the total amount of force exerted up to that moment. It does not give any indication of the incremental amount of force being applied at that instant. Thus, such a device measures cumulative combing resistance rather than instantaneous combing resistance. Cumulative combing resistance does not supply any indication of peak forces experienced by the hair, peak forces being the type of force most damaging to hair.
One method of reducing split ends is to continuously monitor the magnitude of force applied to a tress of hair during the entire length of each combing stroke, allowing a person using the apparatus to keep the force applied to each portion of the hair tress within an acceptable range. Such an apparatus could be used in the home, or used by a hair care specialist as a means of training a person to reduce the force applied in combing her hair. An instantaneous feedback of that force is an essential element in learning to associate the pulling sensation experienced by the scalp with the force being applied, and thus, keep that force within an acceptable range.
Accordingly, an apparatus is needed which can be used to measure the force used in combing hair while it is still attached to the head in combination with a means for providing instantaneous feedback of that force.